"Right at the start we sat down and thought what story we wanted to tell. We knew we had Joker starting off sick from the previous game and we wanted to play on that idea.

"Pretty early on we hit on this idea of Joker poisoning Batman and the two of them having this kind of shared goal, but with diametrically opposed world views. We felt that gave a lot of opportunity to interact in interesting ways, and I guess then we sort of knew that we wanted that story to have resonance in the universe."

He continued: "You invest time in a game and this story, and you want to feel like the universe is affected by the events you play. We didn't want it to feel hollow - Joker starts off poisoned, Batman gets poisoned, where does that story go?

"We knew people would be thinking, 'Obviously they're not going to kill Batman or Joker, right?' We felt killing Joker was a really striking end. It was almost taboo, like it was something we could never do. That would be interesting."